The above described acoustic panel is already known from the DE-U-9300151, in which an underlying panel consisting of a porous, elastic synthetic resin is improved regarding its degree of sound absorption when it is covered (on one side or both sides) with thin cover layers of a fleece or fabric of glass, plastic or natural fibers, whereby in a conventional manner also the dimensional stability of the entire acoustic ceiling can be improved. To connect the cover layer(s) to the underlying panel an adhesive is used, which is thereby supposed to be applied in such a manner that the porosity of the underlying panel and of the cover layers is not bothered and the air in the room can circulate through the acoustic panel.
It is also already known from the Offenlegungsschrift DE 31 47 174 A1 to use for the cover layer a layer connection of the actual cover layer and of a sandwich-type plasterboard so that the controversial conditions can be met. The cover layer is thereby fastened on the underlying fabric by means of a binding agent; the same binding agent is used for gluing the underlying fabric to the sandwich-type plasterboard, which is used in a perforated design in order to achieve the desired sound permeability to the actual soundabsorbing underlying panel.
The use of an underlying fabric for the cover layer is unfavorable because its structure can show on the room-side visible surface of the cover layer mainly when the connection of the acoustic panel is compressed by means of a pressure plate, which is necessary already because of the adhesive layer. When the underlying panel consists of a granulation mixed with a binding agent, then moreover such a compression assures at the same time the binding of the individual granules. The use of such a granulation is already described in the Patent DE 14 84 072 C3 where the binding agent envelopes both the individual granules and also causes the holding together of the granules.
The use of swelled perlites or vermiculites as granulation for the underlying panel has been known already for a long time in particular for nonburning acoustic panels, just like the connection of the granulation by means of an inorganic binding agent. These acoustic panels also show the same disadvantages as they have been discussed in detail already above.
The purpose of the invention is therefore to disclose a process for the manufacture of an acoustic panel of the above in detail identifies type and an acoustic panel where the discussed deficiencies of the state of the art are avoided and a statically relatively highly stressable acoustic panel is constructed both with a good sound absorption and also an inability to burn. The manufacture of such an acoustic panel is thereby supposed to be possible without any problems and inexpensively. The adhesive is not supposed to significantly influence the porosity of the acoustic panel.